Make sure "del d[n]" is properly supported. Was necessary because the

same method that implements __setitem__ also implements __delitem__.
Also, there were several good use cases (removing items from a queue
and implementing Forth style stack ops).

1 files changed, 14 insertions, 3 deletions

diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index e8d9ce49c7..9b857c5d47 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -90,6 +90,20 @@ class TestBasic(unittest.TestCase):
             l[i] = 7*i
         self.assertEqual(list(d), l)
 
+    def test_delitem(self):
+        n = 500         # O(n**2) test, don't make this too big
+        d = deque(xrange(n))
+        self.assertRaises(IndexError, d.__delitem__, -n-1)
+        self.assertRaises(IndexError, d.__delitem__, n)
+        for i in xrange(n):
+            self.assertEqual(len(d), n-i)
+            j = random.randrange(-len(d), len(d))
+            val = d[j]
+            self.assert_(val in d)
+            del d[j]
+            self.assert_(val not in d)
+        self.assertEqual(len(d), 0)
+
     def test_rotate(self):
         s = tuple('abcde')
         n = len(s)
@@ -476,9 +490,7 @@ deque(['c', 'b', 'a'])
 
 
 
-
 >>> def delete_nth(d, n):
-...     "del d[n]"
 ...     d.rotate(-n)
 ...     d.popleft()
 ...     d.rotate(n)
@@ -524,7 +536,6 @@ h
 >>> print maketree('abcdefgh')
 [[[['a', 'b'], ['c', 'd']], [['e', 'f'], ['g', 'h']]]]
 
-
 """